![]() ![]() How will the precipitation distribution function change at various temporal scales? How will seasonal distribution of precipitation change? How will the geographic distribution of precipitation change across Spain? ![]() Main water-related uncertainties in climate change applied to Spain How will the mean annual precipitation and inter-annual precipitation variability change for Spain? There is no doubt they will involve greater departures from current long-term means than will global changes.įigure 1. Regional climate changes are even more difficult to predict than global changes. Predictions of how much temperature will rise in the 21st century are uncertain because the response of the climate to changing greenhouse gas concentrations, the rate of ocean heat uptake and the effects of cloud cover and aerosols are all poorly quantified.įuture natural influences on climate, such as solar output and volcanic eruptions, are at present unpredictable, and so are future levels of methane in the atmosphere.įuture sea-level changes are uncertain because of the difficulty of predicting precipitation on Antarctica and of determining the stability or otherwise of the West Antarctic and Greenland ice sheets.Īnthropogenic influences, such as world population growth, the nature of technological and economic development, the effects of land-use changes and the success or otherwise of efforts to restrain the growth of greenhouse gas concentrations in the atmosphere are uncertain. However, it seems likely that global temperatures varied more over the last century than over the preceding millennium. The record of global climate change in the historic past is uncertain because reliable instrumental records are limited to the last century or two, and to only a small proportion of the globe. Key Sources of Uncertainty in Climate Change The Working Paper concludes with an overview of past, present and future climate change and with a summary of the main ideas discussed throughout the text. Then, an analysis of how GHG have been measured is followed by a discussion of the different GHG, natural and human-induced events that have a significant bearing on climate change. The following section presents in a stylised fashion the key features of uncertainty and how it relates to climate change. It analyses the main elements that explain natural climatic change and reflects on the high level of uncertainty in the system, which in many ways is inherent to the system itself, and presents the latest evidence. This Working Paper reviews the main reasons why definite and conclusive evidence in the field of climate change is almost an impossibility. Because of their doubts they see measures to restrict the burning of fossil fuels as being only harmful, liable to restrain future economic growth and likely to cause greater poverty in the developing world. ![]() They may even argue that the beneficial fertilising effects of carbon dioxide outweigh any detrimental effects of the potential warming it may cause. Some believe that there have been changes in global temperature in historic times exceeding any that have occurred since the beginning of the industrial revolution. They point to the views of many scientists and publicists who disagree with climatologists on the influence of greenhouse gases and who point to what they consider to be more important natural influences on climate, especially volcanic eruptions and variations in solar radiation. They are inclined to believe that any warming that may have taken place in recent years is no more than a fluctuation of the kind that has happened many times in the past and is unlikely to persist for any great length of time into the future. ![]() Many non-climatologists are unconvinced that mankind is capable of changing the climate. Most climatologists are convinced that global temperatures have increased since the beginning of the industrial revolution and that the increase is mainly attributable to increased concentrations of greenhouse gases of anthropogenic origin in the atmosphere, especially carbon dioxide, and that if nothing is done to restrict future inputs global temperatures will continue to increase with potentially disastrous consequences, including water shortages in many areas, greater weather extremes and coastal flooding. The lack of agreement on effective measures may also reflect uncertainty that the warming detected over the last few decades is, in fact, attributable to human activity and uncertainty that climate will continue to get warmer and sea-level to rise if the input of greenhouse gases (GHG –see Glossary–) to the atmosphere is not greatly reduced. The Copenhagen meeting on climate change reflected the conflicting aims of those countries that industrialised at an early stage and are mainly responsible for current high greenhouse gas levels, those that are now in the course of rapid industrialisation, and those that remain undeveloped. ![]()
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